`Zero-Cost Exceptions' ("ZCX"),
which uses binder-generated tables that
are interrogated at run time to locate a handler.

`setjmp / longjmp' ('SJLJ'),
which uses dynamically-set data to establish
the set of handlers

Most programs should experience a substantial speed improvement by
being compiled with a ZCX run-time.
This is especially true for
tasking applications or applications with many exception handlers.}

This section summarizes which combinations of threads and exception support
are supplied on various GNAT platforms.
It then shows how to select a particular library either
permanently or temporarily,
explains the properties of (and tradeoffs among) the various threads
libraries, and provides some additional
information about several specific platforms.